Where to Biopsy to DetectHelicobacter pyloriand How Many Biopsies Are Needed to Detect Antibiotic Resistance in a Human Stomach

This study aims to determine the gastric distribution, density, and diversity ofHelicobacter pyloriinfection. Subtotal resection of the stomachs of threeH. pylori-infected and asymptomatic obese patients were collected after a sleeve gastrectomy. Distribution and density ofH. pyloriwere determined using culture and RT-PCR on multiple gastric sites (88, 176, and 101 biopsies per patient). Diversity ofH. pyloristrains was studied using antibiotic susceptibility testing, random amplified polymorphism DNA (RAPD) typing andcagAgene detection on single-colony isolates (44, 96, and 49 isolates per patient).H. pyloriwas detected in nearly all analyzed sites (354/365 biopsies, 97%). Antral density was higher in one patient only. The three stomachs were almost exclusively infected by an antibiotic-susceptible strain. One clarithromycin-resistant isolate in one biopsy was detected in two stomachs (1/44 and 1/49 isolates), while in the third one, eight (8/96 isolates) metronidazole-resistant isolates were detected. DNA typing showed infection withcagA-negative strains for one patient,cagA-positive strains for a second patient and the third patient was infected with two different strains of distinctcagAgenotypes. Infection withH. pyloriis shown to spread to the whole surface of the stomach, but a possibility of minor sub-population of antibiotic-resistant clones, undetectable in routine practice.